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 The Edible Schoolyard Continues to Grow Nov/Dec 2004 High Fructose Nation Sept/Oct 2004 Viva Las Vegas! July/August 2004 Experiments Vs Experience V.1 - A Review March/April 2004 A Day in the Life Jan/Feb 2004 The Skinny on Dietary Fats Jan/Feb 2004 The Basics of Eating Right April 2003 Vegetarian Bodybuilding Jan/Feb 2003 Fitness Water: Fountain of Youth? Nov/Dec 2002 Glutamine: Conditionally Essential? Jan/Feb 2003 Thermogenic Aids March 2003 Flaxing Your Muscles August 2003 |
 By Kristin Reisinger, MS RD [Originally published in Exhilarate Magazine November 2003] For such a skinny little word comprising only three letters, fat is a multi-faceted macronutrient critical to our diet, consisting of many different forms and possessing many unique characteristics. Monounsaturated, saturated, polyunsaturated, essential fatty acids and trans-fats -- what does this all mean? In order to understand the many benefits and appreciate the differences between fats, a brief understanding of their chemical properties is necessary. Like themes and variations on a Mozart melody, each type demonstrates resemblance to another, yet remaining magical unto itself. Let me explain. An Overview Dietary fats consist of saturated and unsaturated fat and can be liquid or solid at room temperature. What makes one different from the other has to do with molecular structure and the number of double bonds and carbon molecules in that structure. To make this painless, a saturated fat has zero double bonds, fully saturated, and is solid at room temperature (butter). An unsaturated fat has at least one double bond (monounsaturated) or more (polyunsaturated) and is liquid at room temperature (oils). A trans-fat is an altered version of a fatty acid and is a result of a process called hydrogenation. These fats have been synthetically made into a solid from a liquid (margarine). This type of fat is generally found in processed items because it increases the storage life of foods and is also significantly cheaper for manufacturers to use than butter or pure oils. Some dietary fats, like unsaturated and essential, are critical to the diet because they are building blocks for the production of cholesterol and sex hormones, provide structure for cells and act as transporters for fat-soluble vitamins (vitamins A, D, E and K) throughout the body. Different fatty acids have different roles in human physiology while some have none. All dietary fats provide a concentrated source of energy at 9 calories per gram. And like amino acids (the building blocks of protein), some fats are deemed essential because they cannot be made in the human body and must be obtained through nutrition. But which fats are good for me? Which ones increase the risk of heart disease? Which fats are in the foods I eat? And what's all the rage about flax oil and omega-3's? 
The Good, The Bad and the UglyAccording to the American Heart Association as well as the current US Dietary Guidelines, dietary fats should be kept below 30% of your caloric intake with only 10% derived from saturated fat. Saturated fat, the bad fat, has been linked to heart disease as well as raises in blood cholesterol. It serves no other purpose in the body aside from providing a concentrated form of energy. Foods high in saturated fat include cheese, milk, butter, lard, ice cream, palm oil, coconut oil and most other animal products and should be kept to modest levels in the diet. Like saturated fat, trans-fats have also been shown to increase risk of heart disease as well as raise blood cholesterol. These fats have undergone a process known as hydrogenation, which is a commercial process that converts an unsaturated fat into a solid state. The controversy here is that the form it becomes is unnatural, produces toxins, rids the original fat of most nutrients and is harmful to the body. These fats are typically found in margarine, shortening and most commercially baked and processed foods. The use of trans-fats has become a hot topic recently in the field of nutrition. Accusations have been made that manufacturers use these products to cut costs at the expense of public health and the uninformed consumer. One way or the other, these products are best avoided because over-consumption can result in the buildup of toxins in the body, osteoporosis, cancer, problems with the liver's detoxification system, reduced efficacy of essential fatty acids in the body and increased risk of heart disease. Unsaturated fats, the good fats, consist of monounsaturated and polyunsaturated oils. These include oils such as olive, canola, safflower, flax, hemp, evening primrose, borage and sesame, just to name a few. The unsaturated fat family is the most fascinating because of the variety and sources. The most famous monounsaturated fatty acid is oleic acid common in olive, almond, peanut, pistachio, macadamia, canola and pecan oils. This fatty acid is known to have a reversing effect on atherosclerosis because it helps to keep arteries fluid. It is also common in the Mediterranean diet. The Essentials With regard to nutrition and better health, the polyunsaturated fatty acids are the most diverse consisting of the essential fatty acids, omega-3 (alpha-linolenic acid) and omega-6 (linoleic acid). Both cannot be made in the body from other fatty acids therefore must be taken in through food sources. These EFA's then have the ability to create other fatty acids necessary in the body, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and gamma-linolenic acid (GLA), arachidonic acid (AA), respectively. All have their own unique melodies that they create through our body in order for the entire biological symphony to flourish. Many sources rich in EFA's contain both the omega-3 and omega-6 fatty acids but in varying percentages. Also, an equal amount is not needed in the body between all essential fatty acids. It is recommended that 3-6% of calories for adults come from omega-6's which amounts to 7-14g/day on a 2000kcal diet. The needs of omega-3's in the diet are still unclear but it is estimated at 1-2.5% amounting to 2-5g/day on a 2000kcal diet. 1 tablespoon of flax oil per day supplies about 2% of calories as omega-3's. Flaxseeds and flax oil are the richest source of omega-3's containing 58% omega-3s, 14% omega-6's and the rest from other unsaturated fats. Hemp oil is also a great source of EFA's containing 20% omega-3's and 60% omega-6's, naturally containing a near perfect 1:3 ratio of omega-3 to omega-6 necessary in our bodies. Other sources containing these essential fats include certain fish, avocados, pumpkin oil, walnut oil, kukui nuts and canola oil. Without a source of EFA's in the diet, deficiency can occur resulting in growth retardation, loss of hair, skin problems, susceptibility to infection and a whole host of other problems. The Bottom Line So with all this information, what is the bottom line? As an athlete or someone leading an active lifestyle concerned about overall wellness, a good rule of thumb is to follow the guidelines below. Saturated fat, though proliferating our food supply, needs to be kept at a minimum to achieve optimal health and performance in sport. The majority of calories from fat in the diet should be taken in a more nutritious form, as mono- and polyunsaturated fats. Essential fats need to be taken in through food sources or supplemented with through a rich source like flax oil or ground flaxseeds. Risks of certain disease will diminish, an overall healthier state will be achieved and it will improve performance!
Kristin Reisinger, MS RD, is a New York City-based nutritional consultant, fitness trainer, freelance health + fitness writer and musician. She holds a Master's Degree in Exercise Physiology + Nutrition from Columbia University and is a Registered Dietitian through American Dietetic Association. She is also a competitive figure athlete, former Galaxy competitor, avid snowboarder, rock climber and surfer. She has been competing for over five years and will continue to do so until she is 80. She can be contacted at kristin@kristinreisinger.com. |
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